OneNote UWP / Mobile Sync issue

For more than one year, I have not suffered any significant sync issue, which means Microsoft efforts to improve the sync mechanisms are paying off.

Following a smart advise, I have set a small notebook intended to fit on my mobile phone (small to load fast and avoid sync issues) ; but last week I faced a sync issue on this mobile notebook, which appeared first on OneNote UWP with the following message :

“Sorry… This section’ file seems damaged. OneNote may repair it, but you shouldn´t modify it in the meantime.”

Clicking on the “Show Sync error” to get some additional info…

…didn´t show any additional info., except that the last sync occurred in January 1st, 1980 (?!) :

Confusingly, I had no error message on OneNote desktop.

And I managed to use this section regularly, on several devices, with my notes properly synched (notwithstanding this scary warning message).

I had the same error message on OneNote mobile (see banner on the top) :

with no more details when looking at “Show Sync error”…

Usually, I look at OneNote Online to get some additional info. about the issue : in this case, I got a sneak notice that the second note of my “Note rapides” section had been deleted, but it vanished quickly and eventually the note content showed up, so I overlooked it.

I was about to give up, and closed the Notebook in OneNote mobile and OneNote UWP, after copying (not moving) my important notes in other Notebooks.

Then, I opened it again to experiment, and got the same message while downloading the second note, but this time, the note won´t open…